The Coriolis Effect

Cirrus Training
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Cirrus Training
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January 24, 2025

The Coriolis Effect

How do pilots take coriolis force into consideration while flying? Or do they? The aircraft is already moving along with the surface of the Earth before it takes off. The rotation of the Earth has no direct significant effect on the aircraft.

The Coriolis Effect is a result of the conservation of angular momentum. As the aircraft flies, it's angular momentum must be conserved, in the absence of any outside forces. So, as the aircraft moves closer to or further away from the axis of rotation - which connects the North and South Poles, the aircraft tends to be deflected off it's path. We see on weather maps the effect of this deflection: cyclones and anti-cyclones rotate according to the rules of Coriolis. In the Northern Hemisphere these winds spiral to the right and in the Southern Hemisphere they spiral to the left. However, the effect is very slight over short distances and even slighter at low speeds. So even though the correction is necessary in principle, it tends to get lost in all of the other corrections that pilots make during a flight.

The most important influence of Coriolis on aircraft is the effect it has on wind direction. Pilots account for winds and make periodic corrections for changing winds, the Coriolis effect is not even felt — even on long-range flights. So, in effect, by the time the pilot has made corrections for the winds, he has also automatically corrected for the Coriolis effect without even thinking or knowing about it.

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